The canonical DTC conversion funnel is typically session → product detail page view → add to cart → checkout start → shipping info → payment info → purchase. Some brands collapse the three checkout sub-steps into a single “checkout completion” stage and some split traffic into category-page then PDP, but the seven-step shape is the practitioner default across GA4, Shopify Analytics, and most BI tools.
Overall site conversion rate equals the product of every step-level rate in the funnel. That decomposition is the point: a flat aggregate CVR tells you the storefront moved, while the step rates tell you which step moved. The arithmetic is what turns a number on a dashboard into an intervention target.
When sitewide CVR drops, the diagnostic question is not “is CVR down” — it is which step got worse. A drop concentrated at PDP-to-ATC, surfacing in add-to-cart rate, usually points to pricing, imagery, or PDP copy. A drop concentrated at checkout-start-to-purchase, surfacing in cart abandonment rate, usually points to checkout flow, shipping cost revealed late, or payment-method coverage. The mapping is where to look first, not deterministic diagnosis.
The conversion funnel begins at session. The marketing funnel above it — awareness, consideration, intent — feeds those sessions and is measured separately, typically with different attribution tooling. Useful funnel reporting segments the step-level rates by traffic source, device, and new-vs-returning, read week-over-week against a stable denominator.